The present invention relates to a locking screw with a synchronized thread as well as a bone plate having a corresponding synchronized thread. Further, the present invention relates to a targeting device for applying a bore tool or a screw to a bone plate, and in particular to a targeting device which corresponds to the bone plate with respect to a coupling.
For treatments of bone fractures by surgery, in particular cases it is necessary to use bone plates and corresponding bone screws for a fixation of fragments of a bone. One of the rising problems when applying a bone plate and a bone screw to a bone is that the bone screw may untighten or become loose with respect to the bone plate, which may result in a bad healing process of the bone fracture, and further may lead to complications during the healing process. Therefore, it is necessary to lock the bone screw with respect to the bone or with respect to the bone plate to avoid the untightening or loosing of the bone screw, while maintaining a sufficient guiding of the screw during application of the screw.
In the past, several solutions for this problem have been proposed, for example to apply an additional fixation plate onto the head of the bone screw in order to press the head of the bone screw against the bone plate. Further, some locking mechanisms have been used in order to block or to clamp the head of the bone screw in the through hole of the bone plate. However, most of the commonly known solutions lack of a particular guiding of the bone screw with respect to the bone plate.